Final answer:
Bipedalism is the term for walking on two feet rather than four, allowing for maintaining posture and lowering the sole of the foot to the ground during various activities.
Step-by-step explanation:
Walking on two feet rather than four is called bipedalism. This is a key adaptation that separates humans and some other animals from quadrupedal locomotion, which is walking on four limbs. Bipedalism allows for a variety of movements and postures, including the ability to lower the sole of the foot to the ground during activities such as foot-tapping or jumping and maintaining posture while walking. This function is developed as infants learn to hold their bodies erect which leads to increased stability while standing. When discussing the aspects of balance in bipedal locomotion, one should consider the stance leg and the step leg. While the stance leg supports the weight on the ground, the step leg is moving forward. Anatomical adjustments like the evolution of the foot arch and the alignment of toes contribute to the efficiency of bipedal walking.